Don’t be ashamed! Every embarrassing travel question you’ve thought of has probably been asked by someone else before—and we’ve got the lowdown on the most blush-inducing queries. Welcome to Travel 101.

"You’re going to think this question is so stupid," a recent travel companion of mine told me over the phone, before we went on a trip to the Caribbean. "You’re going to laugh." I promised her I would do neither, and wondered what she could possibly think was so humiliating that she was afraid to ask me. "After I get off my connecting flight," she began slowly, "do I have to pick up my luggage before I get on the plane to Aruba?" Think the answer is obvious? Not so fast!

Recently, American Airlines announced that it would no longer "through check" bags to a final destination if separate tickets on an airline not affiliated with American are presented at check-in. So if she had been flying two different airlines, she would have had to grab that bag. (Other airlines like Delta and Frontier also have this policy.) In this case, though, I assured her the airline would make sure her suitcase got to Aruba, no need for her to intervene. And I definitely didn’t laugh!

It just goes to show you: "The rules change," says Sally Watkins, travel agent at Century Travel and Cruises in Austin, Texas. Because even seasoned travelers can use a brush-up, we asked travel experts to share questions people have been embarrassed to ask them, along with their no-nonsense answers. What you learn might surprise you.

Sometimes, yes—even if you feel foolish for asking or for letting them lapse to begin with. "People feel really guilty about letting them expire," says travel expert Brian Kelly, better known as The Points Guy. "Most airlines will charge you to get them back, if at all. Or some airlines, like US Airways, are more lenient than others."

Other airlines, Kelly says, will give your miles back to you for free if you do something for them, like sign up for one of their credit cards or do another "certain qualifying activity."

"In general, it never hurts to ask, so don’t feel guilty," Kelly says. "Always ask the airline or credit card company. But it’s not always worth it to pay the price. Always make sure you’ll get more value than what you pay for them."

First-class upgrades are more difficult to score than, for example, being moved to a seat with more legroom in coach, Kelly says. That said, never underestimate the power of that great equalizer: chocolate. (Yes, really!)

"Gate agents at the airport get berated all day long, and being nice and bribing them, whether it’s a box of chocolates or just being super-sweet, you’d be surprised how much that still [counts for]. They have a lot of say. Gate agents are in control of who gets what seats. There are processes, and if coach is oversold and there are some business-class seats, they can still absolutely move whomever they’d like up front."

The takeaway? It doesn’t hurt to try. "You never know," Kelly says. "Go into any situation with an open mind. A simple candy bar to a gate agent could potentially get you first-class upgrade, and if not first, one of the best seats in coach. A small gesture can still go a long way even in 2014."

Unfortunately, no—not in these post-Victorian times, says Watkins, who says she is sheepishly asked this question a lot.

"The days of porters in the rail station are gone, unless you pay for a private service," she says. "Otherwise, you are responsible for getting your luggage to your correct train car, and getting it up whatever little steps there are, and putting it on the luggage rack."

She offers this step-by-step advice to people who are lugging their things across Europe, especially:

"At the end of each car, there will be shelves to put your luggage," she says. "Some trains have overhead racks for luggage; some trains have seats that are back to back, leaving a triangle in between, where they can slip a suitcase. It all depends on how that particular train is configured. I recommend that if they have smaller bags, in particular, when the train stops at a station, they might want to go back and lurk around the luggage rack. I used to never worry about that, but there have been reports that, when the train makes a quick stop, some guys jump on and grab a bag and take off, and then the train leaves. I’ve never had it happen to anyone, but I have read that."

Whether you’re signing the bill in a restaurant, taking a sightseeing tour, or trying to score discounted tickets to a hot Broadway show via your hotel concierge, his one’s a toughie, and the answers you’ll hear often depend on whom you’re traveling with.

"A New Yorker is going to tell you different amounts for the USA than someone in almost any other part of the USA is going to tell you," says Tim Leffel, author of The World’s Cheapest Destinations. "That’s why people struggle with it so much, and why the whole practice causes so much anxiety. I’m convinced it’s a huge factor in why all-inclusive resorts are so popular."

The best thing to do is gather as much information as you can, preferably from locals or, if you’re feeling bold and friendly, others in your group. Tipping apps, like GlobeTipping ($0.99; iTunes), can nudge you in the right direction too.

"I rely on guidebooks, culture shock kinds of books, and local advice," Leffel says. "If a local says they would give $5 a day to a guide, based on local norms, but the ‘suggested amount’ from the tour company is $20 per day, then I know what the extremes are and can leave an appropriate amount in the middle."

"The answer is: It depends," Kelly says. "Everyone should know what their FICO score is. Some credit-card companies, like Barclays, will give it to you for free. FICO-score-wise, generally you want to be above 700, but I definitely know people who have been below 700 and have gotten approved for premium cards.

"I think the biggest thing to take into account is not necessarily just your score, but how much available credit you have, and how much debt you’re carrying. If you’re carrying a huge amount of debt, the chances of getting approved for a brand-new card or a premium card are low. You may have a blemished score or mistakes from years ago, but credit card companies can see past that. I think the biggest factor is how much of a balance you’re carrying every month. If you can get that down, the chances of getting approved increase dramatically."

"Generally, yes, there will be someone who speaks English," she counsels them. "There could be some awkward moments when no one does, but very often the next person that walks up to the counter will speak English and will interpret. Or you can get by drawing pictures and using hand gestures."

"You’re still going to sound like an American, but it’s appreciated," she says. "It shows that you’re trying."

It’s a fair question! A GPS that speaks only foreign languages is a scene from a buddy comedy waiting to happen. But that’s not the case abroad, funny as it is to imagine.

"I always say, ‘Yes, it can be set to English,’" Watkins says. "When you pick it up, with the car, make sure that it is before you take off. Generally, GPS’s are not as frequently built into a car as they are here now. So unless you get a premium model of some kind, you generally get a handheld GPS. Just make sure. Turn it on, see that it does get English, and if not, ask the car rental people to adjust it."

These days, you probably will, says Watkins, who says she hasn’t booked a room for a guest without its own bathroom in years. Still, if you’re on a strict budget and going with the lowest priced hotel room you can find, there is a chance you’ll be sharing a restroom with the whole hallway.

"Anything above about a two-star hotel these days is very likely to have its own bathroom," she says. "The term that they use most in Europe is ‘en suite’—that’s saying it’s connected to your room. There are one-star hotels and two-star hotels that are above hostels that may have a mix of rooms—’X’ number of rooms with private baths and ‘X’ number of rooms with a shared bath. If that is important to you, find it in a description. Or write the hotel directly and ask, ‘Do all of your rooms have private baths?’"

Similarly, nail down the air conditioning situation if that’s a pressing concern of yours, Watkins says: "There still are hotels that have A/C in their public areas, but not in the individual rooms. You need to ask, ‘Do you have air conditioning in the bedroom?’"

Magazine subscriptions, hotel rooms, concert tickets, rental cars, and gift cards are a few of the many non-airline-ticket ways you can spend your miles. Whether you should is your call.

"No matter what your redemption is, if you’re happy with it, then that’s all that matters," Kelly says. "And that’s it. Period. Are non-flight redemptions the best way to use airline miles? Pretty much no. You’ll probably get more value elsewhere, but I know a lot of people who are mileage rich and cash poor, and sometimes redeeming miles to cover expenses that you’d otherwise have to pay out of pocket can make sense, even if they’re not the ultimate best way."

This is where miles get tricky, says Peter Greenberg, host of TV’s "The Travel Detective." It’s best to assume the path to a free travel ticket will be rocky, to say the least.

"People are still operating under the delusion—helped in no small part by the airlines’ effective marketing and advertising campaigns on their mileage programs—that the minute you get to 25,000 miles you’ll be on a beach with a piña colada in your mouth. Hardly the case. Earning miles is one thing. Redeeming them often takes herculean efforts at a time when airlines are flying 86 percent load factors and have rapidly decreasing financial incentive for redeeming those miles."

Another thing to bear in mind: whether "free" is really free when credit cards get involved.

"If 54 percent of all mileage earned is earned on the ground with credit cards tied to individual airline mileage programs, that means for every 25,000 miles you earn, you’ve spent on average $14,000!" Greenberg says. "And that’s before you find out there are no seats available at 25,000 miles—only 50,000 miles. Ouch."

In first-world countries like those in Western Europe, the region that Watkins says she was asked this question about, yes. As for the rest of the world, especially developing nations, double-check with your hotel or resort about the safety of its water supply, and go to cdc.gov/travel for country-specific health warnings and guidelines.

If you’re still wary, as a general rule, the Centers for Disease Control says it’s OK to drink sealed bottled water, disinfected water, ice made with bottled or disinfected water, carbonated drinks, hot coffee or tea, and pasteurized milk. Steer clear of tap or well water, ice made with tap or well water, drinks made with tap or well water, and unpasteurized milk.

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